Why do we need auxiliary gas when we use a fiber laser cutting machine to cut metal materials?

There are four reasons: we use auxiliary gas when using a fiber laser cutting machine.
1. First, the assist gas will chemically react with the metal material to increase the working capacity.
2. Second, blow off the slag with air and clean the slits.
3. Third, the gas will cool the area around the slit, which avoids material shape changes.
4. The most important but the most important. The focusing lens is protected from the combustion products caused by the high temperature of the laser beam.
Typically, O (oxygen), N (nitrogen) and air will use as an auxiliary gas for fiber laser cutting.

Their functions are as follows.
N: Nitrogen is used to cut non-ferrous metals such as stainless steel and aluminum. It cools and protects the material. Because such materials are easily blackened by oxygen. This black phenomenon can  avoide by using nitrogen.
Applicable materials: aluminum, aluminum alloy, stainless steel, galvanized steel, brass.

O: Oxygen is used to cut carbon steel. Because carbon steel contains many carbon impurities. Using O can greatly increase the speed.
This also speeds up the cutting speed. However, there are disadvantages that the cutting surface will be black.

The cutting surface is black or light yellow.

Applicable materials: stainless steel, carbon steel.

Air: Air Compressor provides air. The price is very low. Although the air contains about 20% oxygen. Cutting efficiency is much lower than oxygen, almost the same as nitrogen.

The cutting surface is yellow.

Applicable materials: aluminum, aluminum alloy, stainless steel, galvanized steel, non-metal, etc.

Argon: Very expensive, unaffected by oxidation and nutrients. The cutting surface is yellow.